- What is your favorite time of the year to go on a date?
- Most people would probably say the summertime
because everyone wants to get naked,
but to me it's the fall.
- I think it's fall.
I mean, it's cuffing season for a reason, right?
- Summer. If we're not going, like,
to an air-conditioned place or swimming,
and I'm just, like, drenched in sweat,
and they're drenched in sweat,
I don't feel like that's good first-date material.
- For as long as humans can remember,
the environment has always impacted
who we want to keep in our lives.
But now, with climate change,
dating and mating have never been hotter,
and that's not always a good thing.
As our planet warms to unthinkable temperatures,
some animals -- and even people --
are forced to rethink dating habits
they've been using for generations
in order to beat the heat.
Many animals mate with whomever has the grandest features,
a possible sign of good fitness or health.
This sexual selection has been a big driver
in how some species evolve as a whole.
For example, a female peacock may choose to mate
with the largest, most colorful plumage,
and, as a result, these flashier males
get more opportunities to pass down their genetics.
Enter climate change,
which is mixing longstanding mating preferences
with new survival challenges.
In horned animals, like cows and goats,
females typically prefer males with the largest horns.
Larger horns also help males manage their body heat
more effectively and keep them cool during warmer seasons,
which will come in handy as global temperatures rise.
So, in this case, climate is reinforcing a female's
preference for larger horns.
But sometimes climate change
is at odds with sexual selection.
Female dragonflies typically prefer males
who flash their wings with deep, robust colors.
But those dark, seductive shades also absorb heat,
warming up the insect by as much as 3 1/2 degrees Fahrenheit,
and that just drains too much energy in today's climate.
Researchers have found that in recent decades,
males have been losing the bling in their wings
to better survive warmer temperatures,
even if it disappoints the ladies.
Take the fruit fly.
Females typically choose only one male.
But male fruit flies have a harder time
producing healthy sperm in higher temperatures.
As a result, female fruit flies have adapted,
increasing their number of mates in warmer environments,
as shown in lab studies.
It's tough to tell how a warming planet
will impact how we humans choose our mates.
But there is some evidence that may show our dating
and mating has already changed.
One study showed that on days when it hit above
80 degrees Fahrenheit,
the birth rate decreased by 4/10 percent 8 to 10 months later.
Our sex lives were literally too hot to handle.
And OkCupid data showed that young daters
who said that they were more concerned with climate change
got more matches and likes.
We decided to take to the streets to see how climate
and weather are impacting the dating lives
of whoever would talk to me.
He is a 10, but he doesn't believe in climate change.
- Oh, zero, negative, like, 5.
- They would just be a stupid 10.
- Oh, gosh, that is rough.
Probably a 4, actually.
- At least a 4,
and then I'd like to hear some reasons on that.
- They're a 2, but they compost. - Composting is cool.
My roommate just got into composting,
and she's been teaching me a little bit about that.
- Do you want to date your roommate?
- I do not.
[laughing] No!
- He is a 2, but he composts. - Still a 2.
I don't think it's that -- -They might be a 1.
- No matter how you look at it,
climate change is disrupting how males and females
have traditionally chosen their mates.
The environment has always impacted mating
and sexual selection.
But rapidly rising temperatures are pushing animals
to adapt faster than ever before in modern history.
And that includes their pickup techniques.
Will animals be able to adapt and adapt fast
enough to beat the heat?
Only time will tell.